The government changed rules on banking fraud in 2007
One of Britain's top prosecutors has said victims of fraud have to be "lucky" to get it investigated.
David Kirk, director of the Fraud Prosecution Service for England and Wales, said the crime was increasing because of the credit crunch.
He called for it to be made more of a priority, with more dedicated officers deployed around Britain.
Ministers say police probes are improving and the number of prosecutions has been rising.
Fraud is estimated to cost about £20 billion a year - but Mr Kirk told the BBC that pressures on police budgets had led to a drop in fraud squad officers from 600 to 400 over the past decade.
He said he welcomed coming improvements but believes more must be done.
"Police priority for fraud investigation is low - in fact it isn't on their list of priorities," said Mr Kirk.
"If you were an ordinary member of public taking your complaint about a fraud along to your local police station, you would probably find that you would not get much response - you would have to be quite lucky to get it investigated.
Boiler room scams
"That's not to say that fraud squads up and down the land don't do a fantastic job - they are some of the best officers in the police force."
Mr Kirk said a great deal of fraud was now taking place in the banking sector and through "boiler room" investment schemes selling worthless shares.
"Mortgage fraud has come back with a vengeance because of the credit crunch and organised crime is moving into mortgage fraud," he added.
In 2007, the government changed the rules over banking fraud, telling customers that banks would handle the complaints and decide whether to refer them to the police.
But figures from the Attorney General show the number of cases has doubled in the two years since the launch of the Fraud Prosecution Service - reaching 297 in the quarter to this September.
And Home Office minister Vernon Coaker said the City of London Police would soon become the national lead on fraud with 40 additional officers being recruited.
"The government has allocated £29 million over three years to implement the recommendations of the Fraud Review.
"This includes the creation of a National Fraud Strategic Authority, to start operating next month.
"A new national lead police force on fraud is being set up, through the City of London Police, to lead some investigations and reinforce the policing response.
"It will provide counter-fraud specialist training, best practice and support to police forces in England and Wales."
But Mr Kirk added: "If you are a victim of a violent assault, that's a terrible thing. But it's also awful to have your life savings stolen by a fraudulent investment scheme that will ruin the rest of your life. It's not a victimless crime."